Actuator for tool moving mechanism

ABSTRACT

An actuator suitable for use with apparatus for moving a tool along a predetermined path and in accordance with a preselected sequence wherein the actuator includes a rotatable cam adjacent to a surface adjustably mounted for rotation about an axis parallel to the axis of rotation of the cam with the surface spaced laterally of its axis. A lever having one end manually in engagement with the cam and the surface is mounted for movement in a predetermined direction in response to the rotation of the cam and as the end of the lever moves along the surface. The lever is adapted to be coupled to a tool so as to form part of said apparatus.

Diepeveen Nov. 19, 1974 ACTUATOR FOR TOOL MOVING MECHANISM [76] Inventor: John C. Diepeveen, 1737 Kimberly Dr., Sunnyvale, Calif. 94087 [22] Filed: Feb. 24, 1972 [21] Appl. No.: 229,058

Related US. Application Data [62] Division of Ser. No. 18,153, March 10, 1970, Pat.

FOREIGN PATENTS OR APPLICATIONS 7 688.478 3/1953 Great Britain 74/53 771,075 7/l934 France 74/53 Primary Examiner-Samuel Scott Assistant Examiner-Wesley S. Ratliff, Jr. Attorney, Agent, or FirmTownsend & Townsend [57] ABSTRACT An actuator suitable for use with apparatus for moving a tool along a predetermined path and in accordance with a preselected sequence wherein the actuator includes a rotatable cam adjacent to a surface adjustably mounted for rotation about an axis parallel to the axis of rotation of the cam with the surface spaced laterally of its axis. A lever having one end manually in engagement with the cam and the surface is mounted for movement in a predetermined direction in response to the rotation of the cam and as the end of the lever moves along the surface. The lever is adapted to be coupled to a tool so as to form part of said apparatus.

16 Claims, 10 Drawing Figures SHEEI 1 OF .7

PAH-INTE uav 1 9mm PATENTLL: T43! 1 91974 3. 848.473

SHEET 8 OF 7 FIG. 8

2ND SEARCH 9 CAM TORCHSWCAM: Y

ZNDBOND CAM v TAIL PUL'LER 1 CAM HOMING CAM W momRswcmw w A V A 2" BOND TIMERSWCAMIQ LOOPING CAM REM OTE INDEX IMPULSE I m PATENTEL w 1 91974 3'. 848.473

SHEET 7 BF 7 ACTUATOR FOR TOOL MOVING MECHANISM This is a division of application Ser. No. 18,153, filed Mar. 10, 1970, now US. Pat. No. 3,653,268 and entitled, TOOL MOVING MECHANISM.

This invention relates to improvements in tool handling machines and, more particularly, to an actuator for apparatus for moving a tool in a sequential manner into and out of a number of different operative positrons.

While the present invention might well be suitable for a number of different uses, it is especially suitable for use as part of the mechanism for moving a thermal compression bonding tool into and out of operative positions at which connecting wires can be bonded to a die and to a number of terminals or posts on a frame for supporting such a die. The die can comprise, for instance, an integrated circuit chip or a hybrid component using semiconductor material to form an electronic circuit. Since components of this type are extremely small and must be handled with great care, it is important to bond the various wires to the various locations on the die and terminals in a manner such as to assure that good, firm bonds are made without structural damage to the die and terminals.

Bonding devices of conventional construction have structural drawbacks which make them unsatisfactory for one reason or another. For instance, they are generally quite complex in construction and oftentimes difficult to operate without causing structural damage to a die unless very skilled operators are available to operate them. Also, in such a device, the tool often bounces on the workpiece because of the way in which the tool is caused to approach the workpiece.

The present invention provides an actuator for apparatus which, in operation, circumvents the problems encountered with the operation of conventional thermal compression bonders. To this end, the actuator of this invention can be used as the basic element by which a thermal compression bonding tool can beadjustably moved so that the tool can approach a die or any ofa number of adjacent terminals without the need for very skilled machine operators.

The advantages of the actuator of the present invention are realized by the provision of a cam mounted for rotation on a support adjacent to a rotatable member having an actuator surface spaced laterally from its axis of rotation, the axis of the member being generally parallel to that of the cam. A lever having one end biased into engagement with the cam and the surface is adapted to be coupled to a tool-carrying slide unit of the aforesaid bonding apparatus so that movement of the tool can be effected in response to the rotation of the cam and as the end of the lever moves along the actuator surface. This surface can be adjusted in inclination so as to permit the latter to move through greater or lesser distances depending upon the operative position of the surface.

The primary object of this invention is to provide an improved actuator for use in moving a lever wherein the actuator includes a cam rotatable about a first axis and a surface-defining member rotatable about a second axis with the surface of the member being substantially flat and spaced from the axis of the member so that. when one end of the lever is simultaneously biased against the surface and the cam, the lever will move as a function of the rotation of the cam and as the lever moves along the surface.

Another object of this invention is to provide an actuator of the type described wherein the member has a crescent-shaped projection thereon defining said surface, with the latter being on a chord with respect to the axis of rotation of the member so that the surface can be adjustably positioned to effect movement of the lever along the surface as the lever is deflected by the cam when the latter rotates about its axis.

A further object of this invention is to provide an actuator of the aforesaid character wherein the rotatable member has an arm coupled thereto to permit the latter to be manually adjusted so as to adjustably position the actuator surface in accordance with a desired movement of the lever relative thereto.

Other objects of this invention will become apparent as the following specification progresses, reference being had to the accompanying drawings for an illustration of the invention.

In the drawings:

FIg. 1 is a side elevational view of the housing for the mechanism of this invention with the mechanism being shown within the housing in dashed lines and illustrating a bonding tool adjacent to a die holder for bonding wires to the die;

FIG. 2 is an enlarged, top plan view of the mechanism of the invention;

FIG. 3 is a side elevational view looking in the direction of lines 3-3 of FIG. 2;

FIG. 4 is a side elevational view of the mechanism looking in the direction of lines 44 of FIG. 2;

FIG. 5 is a front elevational view of a portion of the mechanism looking in the direction of lines 55 of FIG. 2;

FIG. 6 is a cross-sectional view looking in the direction of lines 66 of FIG. 2;

FIG. 7 is a cross-sectional view of the mechanism looking in the direction of lines 77 of FIG. 2;

FIG. 8 is a cross-sectional view looking in the direction of lines 8-8 of FIG. 2;

FIG. 9 is a view of a timing sequence showing the relationship between the various cams used to operate the various moving parts of the mechanism; and

FIG. 10 is a bottom plan view of the housing for the mechanism showing the linkage mechanism for moving the die holder with respect to the bonding tool of the mechanism.

The apparatus of this invention is broadly denoted by the numeral 10 and includes a modular mechanism 12 having a reciprocal tool holder or horn 14 which moves in a substantially vertical plane to, in turn, move a die bonding tool 16 coupled thereto toward and away from a die holder or mount 18 carried on a surface 20 on the base 22 of apparatus 10. Mechanism 12 is disposed within an upper housing 24 which is supported by a lower housing 26, the latter being secured in any suitable manner to the upper portion of base 22 in spaced relationship to surface 20 as shown in FIG. 1. A microscope assembly 28 is secured to housing 24 by means of a pivot structure 30 whereby the operator of apparatus 10 can view a die carried by mount 18 on a greatly enlarged scale.

In a general way, apparatus 10 operates to bond a number of connectingwires to various locations on a die defining an integrated circuit, a hybrid circuit or other component, the opposite end of each wire beingbonded to a post or terminal on the frame which supports the die. Thus, the finished product can then be packaged to form an electronic component for use in electronic circuitry.

Initially, a wire 32 carried on apparatus 10 in some suitable manner, such as on a spool or the like, is caused to extend through tool 16 and to project outwardly from its lower end. A hydrogen torch 34 having a tip 36 is provided adjacent to the bottom of tool 16 so that the frame at the torch tip can be used to heat and melt the lower end of the wire to cut the wire and to form a bead thereon to assure movement of the wire downwardly toward a die upon downward movement of horn 14. Tool 16 is heated by an electrical resistance heater 38 by means of electrical power supplied in any suitable manner by leads 40 so that tool 16 does not provide a heat sink for the die, the latter being heated in some suitable manner by a heater (not shown) within mount 18.

Assuming the first bond of the wire to be made on a die held by mount 18, mechanism 12 operates to cause horn l4 and its mounting means to move downwardly from an uppermost or home position to a first search position with the tool spaced above and in proximity to the die, then to a bond position with the tool forcing the bead at the end of wire 32 into bonding relationship to the die, then upwardly to an intermediate search position which is below the home position whereby the tool moves relative to the wire since the wire is attached at its one end to the die, then from the intermediate search position downwardly to a second search position spaced above and in proximity to a terminal or post on the die supporting frame, then into a second bond position wherein the wire is moved into bonding relationship with the terminal on the frame, then finally upwardly to the home position at which torch 34, carried by a pivotal structure 42, iscaused to sweep across the wire to cut the same as well as to heat and melt it to form a bead on the outer end of the wire for the next bond operation.

While the foregoing has been described with respect to making the first bond on the die and the second bond on a terminal or post, it is clear that the first bond could be made on a terminal or post and the second bond be made on the die. Also, mount 18 is shifted to permit tool 16 to be in the proper positions directly above the locations at which the bonds are to be made. To shift the mount, a pivot assembly 44 (FIG. 10) is provided in base 22 below surface 20, such assembly being here inafter described in greater detail. The operator of apparatus l grasps knob 46 at one side of the apparatus, the knob being secured to a rod 48 which permits manual manipulation of assembly 44, the latter being connected to mount I8 by two spaced pins 49 which project upwardly through two openings 51 (FIG. in base 22. Pins 49 are complementally received within bores in the bottom of mount 18 so that the latter can be shifted about simultaneously in two degrees of freedom, namely, from right to left and forward and backward. Thus. the various locations of the die and the various posts of the die-supportingframe can be properly positioned relative to tool 16, the movement of the latter being confined to the vertical plane of movement of born 14.

Modular mechanism 12 is shown in greater detail in FIGS. 2-8 and includes a slide unit 50 providing the mounting means for horn 14 and formed of a front plate 52 and a rear plate 54 adjacent to and directly behind plate 52. Horn 14 is secured to and extends forwardly from plate 52 as shown in FIGS. 5 and 7, horn 14 having an enlarged rear end 56 which is received within an opening in plate 52 adjac'ent to its lower end. Plate 52 has a pair of slits 58 which extend laterally from the opening so as to render the lower portions 60 of plate 52 yieldable whereby a pair of screws 62 can be used to urge portions 60 against enlarged portion 56 of the horn to releasably hold the latter firmly fixed to plate 52. Thus, the horn will move with this plate.

Plates 52 and 54 move downwardly together from the home position to the first search position, then plate 52 moves downwardly relative to plate 54 to the first bond position as plate 54 remains stationary. Then, plate 52 returns to the first search position, following which, plates 52 and 54 move upwardly together to the intermediate search positions, then downwardly together to the second search position, following which, plate 52 moves relative to plate 54 downwardly to the second bond position as plate 54 remains stationary, then plate 52 returns to the second search position, whereupon plates 52 and 54 move upwardly together back to the home position.

Slide unit 50 is mounted for vertical reciprocation by a pair of spaced side plates 64 (FIGS. 2 and 5) which are secured in any suitable manner to a generally horizontal base plate 66 and are interconnected by a brace 67. Bearing means is provided to mount slide unit 50 for movement relative to plate 64, each of plates 52 and 54 having a pair of bearings 68 on respective opposed sides thereof. Each bearing 68 can be of any suitable construction but, for purposes of illustration, it includes a plurality of balls 70 carried by a perforate strip 72 (FIG. 2) disposed between the corresponding plate of slide unit 50 and the adjacent side plate 64. Each strip 72 has a number of holes therethrough in which the corresponding balls can freely rotate. For instance, in FIG. 2, plate 52 is provided with a longitudinal groove 74 while the corresponding side plate 64 has a groove 76 in alignment with groove 74. A pair of spaced rods 78 are disposed in and extend along each of the grooves 74 and 76, respectively. The four rods in the two aligned, facing grooves define tracks for balls 70 to allow for rolling movement of the balls and thereby permit slide unit 50 to move up and down relative to side plates 64. This type of bearing assures substantially frictionless movement of the slide unit, yet substantially eliminates any lateral movement of the slide unit relative to side plates 64. As a result, horn 14 is restricted to movement only in a substantially vertical plane and movements in other directions are positively prevented.

Plate 54 has a top plate 80 secured to it by machine screws 82 so that top plate 80 overlies and is spaced above plate 52 in the manner shown in FIGS. 5 and 7. Plate 80 has a first hole 84 (FIG. 2) therethrough whereby access to an adjustment screw 86 can be had, screw 86 being threaded into plate 52 from the upper margin thereof and having a lower end provided with a spherical tip 88 (FIG. 5). Plate 52 has an opening 106 therethrough intermediate the top and bottom margins thereof. Tip 88 of screw 86 projects into opening 106 and is normally in engagement with a disk-like roller 90 carried on a shaft 92 (FIG. 7) secured to a pair of arms 94 (FIGS. 5 and 7) rigid to a plunger 96 (FIG. 7) which is shiftably mounted in a sleeve 98 secured to and extending rearwardly from plate 54. A pin 100 on plunger 96 is disposed within a slit 102 in sleeve 98 to prevent rotation of plunger 96 and thereby roller 90 so as to keep the axis of shaft 92 perpendicular to the length of screw 86. In this way, roller 90 can move freely with respect to screw tip 88 when plunger 96 is moved in a direction toward the left when viewing FIG. 7. A coil spring 104 engaging the rear surface of plate 54 and coupled with pin 100 biases plunger 96 to the right when viewing FIG. 7 and into engagement with the flat front face 105 of a projection 107 carried by an arm 109 mounted for pivotal movement relative to and about a shaft 111 spanning the distance between and rotatably mounted on side plates 64.

Roller 90 and arms 94 also extend into opening 106 as shown in FIGS. and 7. The normal position of roller 90 is the position shown in FIG. 7 wherein shaft 92 is in substantial vertical alignment with screw 86. When so positioned, roller 92 prevents any downward movement of plate 52 relative to plate 54 so that plates 52 and 54 can move together as a unit. When plunger 96 is moved to the left when viewing FIG. 7, plate 52 is allowed to move downwardly relative to plate 54 through a distance determined by the distance by which roller 90 moves forwardly of tip 88. The force causing this downward movement of plate 52 is determined by the weights of horn 14 and plate 52 less the upward force exerted on plate 52 by a coil spring 108 (FIG. 5) secured at its upper end to 'top plate 180 and at its lower end to a rigid, horizontal extension 110 projecting forwardly through a second opening 112 in plate 52 (FIG. 5) extending parallel to and being of substantially the same size as opening 106. Extension 110 has a hole through it to receive the tip 112 of a screw 114 threaded into plate 52 from above.

The adjustment in the tension of spring 108 is effected by rotation of screw 114, the latter being loosely received within an opening (not shown) in top plate 80. Screw 114 has a head 116 and is adjustable vertically so that the tension of spring 108 can be increased or decreased to, in turn, cause variations in the effective load or weight exerted on the wire during a bonding operation. In this way, the downward force on the wire can be selected as desired and can be as low as grams or less. This relatively small force is exerted on the wire when plate 52 moves relative to plate 54 through a relatively short distance, i.e., from the first search position to the first bond position or from the second search position to the second bond position. Thus, there will be substantially no tendency for tool 16 to bounce on the die or the frame terminal so as to cause structural damage to the same.

When plate 52 is in the first search position, reciprocal movement of plunger 96 causes plate 52 to move into the first bond position and return. When this plate is in the second search position, reciprocal movement of plunger 96 causes the plate to move into the second bond position and return. Return of the plunger to its starting position is caused by spring 94, resulting in upward movement of plate 52 relative to plate 54 until roller 90 has returned to the position shown in FIG. 7.

The means for moving slide unit 50 and born 14 into and out of the various search and bond positions and the home position includes a number of cams and levers operated in timed relationship so that horn 14 and tool 16 mounted thereon will move in a predetermined sequence under the control of an operator of apparatus 10. The cams include a homing cam 118, a looping cam 120, a bond cam 122 and a second search cam 124. All of these cams are rigidly secured to a shaft 126 spanning the distance between and rotatably mounted on a pair of rear sidewalls 128 and 130 secured in any suitable manner to base plate 66 as shown in FIGS. 24. Bearing blocks 132 rotatably mount shaft 126 on re spective sidewalls so that shaft 126 is essentially parallel with shaft 111.

A pulley 134 is secured to one end of shaft 126 and is coupled by an endless, flexible belt 136 to a second pulley 138 on the shaft 140 of a timing motor 142 secured in any suitable manner to the rear extremity of rear sidewall 130 as shown in FIGS. 2 and 3. The cams and their associated levers, hereinafter described, operate to move horn 14 and slide unit 50 from the home position through the various search and bond positions and then back to home position for each complete revolution of shaft 126. This feature is more clearly set forth in diagrammatic form in FIG. 9 wherein timing lines are shown to illustrate the actions of the four abovementioned cams when they rotate from '0" to 260, namely, for each revolution of shaft 126.

Homing cam 118 has a-single lobe 144 as shown in FIG. 8 and an outer peripheral cam surface which engages a roller 146 rotatably mounted on one end of a lever 148 rigidly secured intermediate its ends to shaft 111. The opposite end of lever 148 is forwardly of shaft 111 and underlies and is engaged by the tip 150 of a screw 152 threadably mounted in plate 54 (FIG. 8) and extending above the same. Screw 152 has a head 154 to permit manual manipulation of the screw relative to plate 154. The weight of slide unit 50 is supported on the front end of lever 148 and, by rotating screw 152, the height of tool 16 on born 14 can be adjusted relative to a die when slide unit 50 is in the first search position.

When lobe 144 of homing cam 118 engages roller 146, slide unit 50 will be at its highest or home position. As shaft 126 moves in the direction of arrow 156 (FIG. 8), lobe 144 moves away from roller 146 and allows lever 148 to rock in a counterclockwise sense when viewing FIG. 8 about shaft 111, whereby slide unit 50 can descend through a distance determined by the configuration of cam 118. Thus, slide unit 50 moves from the home position to the first search position.

A coil spring 164 (FIG. 5) is connected at one end to a lateral projection 166 secured to the proximal side plate 64. The opposite end of this spring is secured to another lateral projection 168 connected to top plate 80. Spring 164 biases slide unit 50 downwardly and thereby biases roller 146 of lever 148 into engagement with the peripheral cam surface of homing cam 118.

When slide unit 50 is in the first search position, bond cam 122 will be rotated by continued rotation of shaft 126 so as to urge arm 109 in a clockwise sense when viewing FIG. 7 relative to and about shaft 111. A roller 158 carried by the rear end of arm 109 normally err-- tool and the wire head is forced against a particular location on a die therebeneath. Bond cam 122 has a first lobe 160 representing the first bond position and a second lobe 162 representing the second bond position. As shown in FIG. 7, the bond cam is in the second search position just prior to moving into the second bond position, assuming rotation of shaft 126 in the direction of arrow 156.

Looping cam 120 operates through a lever 170 (FIG. 4) to move slide unit 50 from the first search position to the intermediate search position and then to the second search position. In the intermediate search position, variations can be made in the length of the loop of wire which spans the distance between the die and a corresponding frame terminal. Looping cam 120 has a single lobe 172 (FIG. 4) which is movable into engagement with a roller 174 (FIGS. 2 and 8) rotatably carried by a shaft on an arm 176 forming a part of lever 170. Arm 176 extends forwardly from roller 174 and is pivotally mounted intermediate its ends on a second arm 178 which extends upwardly from arm 176 as shown in FIG. 4. The forward end of arm 176 is connected to one end of a coil spring 179 whose opposite end is connected to pin 166 projecting laterally from the adjacent side plate 64 (FIGS. 4 and 5). Thus, spring 179 biases arm 176 in a clockwise sense when viewing FIG. 4 so that roller 174 is urged into engagement with the cam surface of looping cam 120.

The upper end of arm 178 is rigidly secured to shaft 111. A second roller 180 (FIGS. 2, 7 and 8) is carried on the same shaft as roller 174; thus, this shaft defines the central axis of rollers 174 and 180. Roller 180 engages a flat surface 182 on a crescent member 184 projecting laterally from a cylindrical bearing member 186 (FIGS. 2, 7 and 8) rotatably mounted in any suitable manner in the sidewall 128. Bearing member 186 has a laterally extending outer portion 188 to which a handle 190 is rigidly secured. The handle extends forwardly from portion 188 and operates to permit manual rotation of bearing member 186 and thereby crescent member 184 so that the inclination of flat surface 182 can be changed. Normally, surface 182 is at least slightly inclined with respect to the vertical. Also,,the common axis of rollers 174 and 180 is substantially axially aligned with the axis of cylindrical bearing member 186.

As lobe 172 of looping cam 120 moves into engagement with roller 174, the roller is forced downwardly along surface 182 so that the common axis of rollers 174 and 180 moves out of axial alignment with the axis of bearing member 186. When this occurs, such downward movement of roller 174 causes a forward movement of arm 176 of levers 170 to, in turn, cause counterclockwise rotation of shaft 111 when viewing FIG. 4. In effect, this causes lever 148 to elevate slide unit 50 and this movement commences when the slide unit at the first search position after plate 52 has moved into and out of the first bond position. Thus, initial movement of lever 148 under the influence of lever 170 causes slide unit 50 to move from the first search position to the intermediate search position.

In the intermediate search position, adjustment can be made in the length of the wire to be looped between the die and a respective frame terminal by manually rotating handle 190 which causes rotation of bearing member 186 about its axis. This is done when lobe 172 engages roller 174, i.e., when the axis of rollers 174 and 180 are out of axial alignment with the axis of bearing member 186. The effect of this handle movement is to change the inclination of flat surface 182 of crescent member 184 and, when the surface becomes more inclined, such as by rotating handle 190 upwardly, arm 176 is moved further forwardly to, in turn, cause additional counterclockwise rotation of shaft 111 and thereby upward movement of the forward end of lever 148. This elevates slide unit 50 further upwardly and thereby increases the length of wire to be looped between the die and a frame terminal. Downward movement of handle 190 has the effect of shortening this loop.

After lobe 172 moves out of engagement with roller 174, the common axis of rollers I74 and 180 returns to substantial axial alignment with the axis of bearing member 186 so that movement of handle 190 will have no effect. However, in most cases, it is desirable to have a constant length of wire in the loop between a die and the various frame terminals; hence, one adjustment of handle 190 is all that is necessary. Also, when lobe 172 of looping cam moves out of engagement with roller 174, lever is allowed to pivot in a clockwise sense when view FIG. 4 so as to allow slide unit 50 to move from the intermediate search position to the second search position.

During the time that slide unit 50 moves into the second search position, second search cam 124 having the single lobe 214 as shown in FIG. 6 is rotated so that lobe 214 moves into engagement with a roller 194 rotatably mounted on a shaft secured to the rear end of an arm 196 forming a part of a lever 192 which is substantially the same in construction as lever 170. Lever 192 also has a second arm 198 which is pivotally mounted at its lower end to arm 196 intermediate the ends of the latter. The upper end of arm 198 is rigid to shaft 111. A coil spring 200 is connected to the forward end of arm 196 and to a lateral projection 202 (FIG. 6) extending from the adjacent side plate 64 to bias arm 196 in a counterclockwise sense when viewing FIG. 6.

A second roller 204 mounted on the same shaft as roller 194 engages the flat surface 206 of a crescent member 208 rigid to a cylindrical bearing member 210 (FIG. 2) which is rotatably mounted in any suitable manner in rear sidewall 130. Bearing member 210 has an outer lateral projection 212 to which a handle 214 is secured, the handle extending forwardly as shown in FIG. 3. While slide unit 50 is in the second search position, the common axis of rollers 194 and 204 is held out of substantial axial alignment with the axis of bearing member 210 by lobe 214 so hat rotation of bearing member 210 upon manual rotation of handle 214 can cause a change in the inclination of flat surface 206. This, in turn, will cause forward or rearward movement of arm 196 and thereby clockwise or counterclockwise movement of shaft 111. In this way, the height of tool 16 from a frame terminal can be varied when slide unit 50 is in the second search position prior to movement of the tool into the second bond position. Thus, the tool can be placed at a desired distance from the frame terminal before the wire is bonded to the same.

To effect the proper timing in the sequence of operation of mechanism 12, a number of timing cams and switches are provided, there being a switch for each timing cam, respectively. As shown in FIG. 2, such timing cams are rigidly secured to shaft 126 and include a timer switch cam 216 having a timer switch 218 associated therewith, a motor switch cam 220 having a motor switch 222 associated therewith, a torch switch cam 224 having a torch switch 226 associated therewith, and a tail puller cam 228 having a tail puller switch 230 associated therewith. The time intervals during which the various switches 218, 222, 226 and 230 are actuated for each cycle of operation of mechanism 12 are shown in hatched areas of the respective timing lines of FIG. 9. Also, FIG. 9 shows the operational sequences of homing cam 118, looping cam 120, bond cam 122 and second search cam 124.

Switches 218, 222, 226 and 230 are secured in any suitable manner to rear sidewalls 128 and 130. Electrical circuitry (not shown) connects these switches to the appropriate circuit elements for actuating the same when the switches are actuated.

FIGS. 4 and 6 show looping cam 120 and second search can 124, respectively, when slide unit 50 is in the home position. FIGS. 7 and 8 show the positions of bond cam 122 and homing cam 118, respectively, when slide unit 50 is in the second search position.

In FIG. 1, torch 34 is carried by a horizontally disposed arm which is mounted for swinging movement about the vertical axis of a shaft 230 secured in any suitable manner to upper housing 24. A flexible hose 232 is coupled in any suitable manner to the source of hydrogen or other suitable gas mixture to support a flame at the tip 36 of torch 34. Hose 232 may be coupled to a control panel having a number of controls, such as a main on-of switch, one or more indicator lights, and a switch for heater 38. Other controls can be utilized, if desired.

To swing arm 228 about the axis of shaft 230, a linkage 234 is provided, the linkage extending rearwardly to an arm 236 mounted for rotation on a shaft 238 which, in turn, is rotated through a limited are by an eccentric 240 secured to the vertically disposed shaft 242 of a synchronous motor 244 mounted in lower housing 26. An impulse or index switch 246 is actuated in response to he rotation of shaft 238 and thereby arm 236. Each time shaft 238 moves the limited distance, arm 228 moves in a direction to cause torch tip 36 to sweep across wire 32 to cut the same and to form abead on the lower end of the wire to make the wire ready for'the next bond operation. Arm 228 is biased in any suitable manner so that it returns to an initial position after a wire has been cut and after a bead is formed on the end of the wire.

Pivot assembly 44, shown in FIG. 10, includes a parallelogram linkage including a pair of rigid side members 248 and 250 and a pair of rigid end members'252' and 254, the side members and the end members all being pivotally interconnected. Rod 48 is rigid to and extends longitudinally outwardly from end member 254 through a slot 258 in the side of base 22. Knob 46 on the outer end of rod 48 is hollow and houses a switch which is manually actuated by a push-button 256 carried by knob 46 in a position accessible to afinger of the hand grasping the knob. The switch is used for controlling timing motor 142 to cause cyclic operation of mechanism 12. Thus, each time the push-button 256 is depressed, slide unit 50 will move from one position to another, such as from the home position to he first search position, or from the first search position to the first bond position and return to the first search position. Suitable wiring (not shown) inteconnects the switch in knob 46 with timing motor 142 and a source of electrical power.

A base plate 260 is secured in any suitable manner to base 22 and extends outwardly therefrom beneath slot 258. Bas plate 260 provides a support over which knob 46 moves the knob being in sliding engagement with the upper surface of base plate 260.

End members 252 and 254 are pivotally secured to side members 248 and 250. Also, a pin 262' pivotally mounts the proximal ends of side member 250 and end member 252 on the underside of base 22 for rotation about a generally vertical axis. Side member 248 can be adjustably mounted on end members 252 and 254 and, to this end, a number of holes are provided in the end members, there being a hole in one end member for each hole in the other end member. When side member 248 is connected in the manner shown in FIG. 10, a ratio of 6 to l is obtained between the movement of knob 46 and the movements of pins 49 which extend through openings 51 and are coupled to mount 18.

When side member 248 is connected by pins to the sec- 0nd or middle set of holes of end members 252 and 254, a ratio of 5 to 1 is obtained between the movement of knob 46 and pins 49. A ratio of 4 to 1 between such movement is obtained when side member 248 is connected by pins to the left-hand set of holes in end members 252 and 254.

Side member 248 is pivotally connected by a pin 264 to an extension 266 rigid to a shiftable member 268 mounted for movement along a rigid bar 270 secured at its ends to a pair of bars 272 disposed in perpendicular relationship to bar 270, bars 272 being shiftably mounted on respective guides 274 rigid to the underside of base'22.

By manipulating knob 46, the operator of apparatus 10 can cause the parallelogram linkage to pivot simultaneously about pins 262 and 264 so as to move pins 49 in any desired direction and thereby move mount 18 coupled with pins 49. When knob 46 moves-to the left as shown in FIG. 10, side member 48 rotates in a counterclockwise sense and causes extension 266 and thereby shiftable member 268 to move to the left also. This causes pins 49 to move to the left-hand sides of openings 51 when viewing FIG. 10. When knob 46 is moved upwardly when viewing FIG. 10, this causes end member 252 to move side member 248 and thereby extension 266 upwardly to, in turn, move pins 49 upwardly in openings 51. Knob 46 can move diagonally in any direction as well as up and down and left and right. Thus, mount 18 can be moved in any desired direction and such movement is limited only by the size of each opening 51.

DETAILED OPERATION With mechanism 12 mounted in upper housing 24 and with tool 16 coupled to horn 14, a die is placed in mount 18 andthe latter is coupled with pins 49 so that the operator of appratus 10 can manipulate or move mount 18 upon movement of knob 46. The operator will view the die by means of microscope assembly 28 so as to properly align the tool with respect to the die and the supporting frame therefor so that bonding of wire 32 to the die and the terminals of the supporting frame can be accomplished.

Initially, a flame will be provided at the tip 36 of torch 34 and a bead will initially be formed on the end of the wire by the torch so that the wire can be carried downwardly to the die upon downward movement of the tool.

Assuming that the die is ready to be bonded, the operator manipulates knob 46 until the tool, as viewed through microscope assembly 28, is directly above the die. The operator then depresses push-button 256 to actuate the switch coupled thereto whereupon timing motor 142 is energized to rotate shaft 126 through a predetermined arc to cause homing cam 118 to be rotated in a direction of arrow 156 so that lobe 144 will move out of engagement with and away from roller 146. This movement allows member 148 to rock in a counterclockwise sense when viewing FIG. 8 to thereby allow slide unit 50 to move from the home position to the first search position. In the first search position, the height of the tool with respect to he die can be adjusted by rotating screw 152 which will either raise or lower slide unit 50 with respect to lever 148. When this adjustement is made, no further adjustment is generally necessary since the first search position is constant for a given type of die in mount 18.

The operator then depresses push-button 256 once again to cause timing motor 142 to be energized for a second time interval to thereby rotate shaft 126 through a second predetermined arc in the direction of arrow 156. This movement causes lobe 160 of bond cam 122 to move into engagement with roller 158 to, in turn, cause arm 109 and thereby projection 107 to be rocked about and relative to shaft 111. This action causes plunger 96 to move to the left when viewing FIG. 7, whereupon plate 52 descends relative to plate 54 so that tool 16 is moved into bonding relationship to wire 32, forcing the latter against a particular location of the die. The wire is held for a predetermined time interval in engagement with the die so as to effect the desired bond. such time interval being capable of being varied such as by a control carried on the control panel of upper housing 24. After this time interval has elapsed. shaft 126 will move through a third predetermined arc. whereupon spring 104 returns plunger 96 to its initial position. causing the return of roller 90 to a location beneath screw 86 to thereby elevate plate 52 relative to plate 54. During this time, rotation of looping cam 120 causes movement of lever 170 in a direction to rotate shaft 111 in a counterclockwise sense when viewing FIG. 4 so that slide unit 50 is moved from the first search position to the intermediate search position. In this position, the operator can manipulate handle 190 to vary the length of the wire extending between the die and the tool so as to vary the loop length of the wire between the die and the terminal on the frame supporting the die. This loop length is varied by changing the inclination of flat surface 182 of crescent member 184. Generally, a single adjustment is all that is necessary since a uniform loop length is generally desired.

The operator then depresses push-button 256 once again to cause energization of timing motor 142 to cause rotation of shaft 126 about a fourth predetermined arc whereupon rotation of looping cam 120 causes slide unit50 to move from the intermediate search position to the second search position. In the last-mentioned position, the second search position can be varied relative to the frame terminal by manipulating handle 214 to vary the inclination of flat surface 206 of crescent member 208 since the common axis of rollers 194 and 204 is out of substantial axial alignment with the axis of bearing member 210 when slide unit 50 is in the second search position. Following any needed adjustment of the second search position, the operator again depresses push-button 256 to cause further rotation of shaft 126 and thereby cause second lobe 162 of bond cam 122 to move into engagement with roller 158 to cause rocking movement of arm 109 in a clockwise sense when viewing FIG. 7 to thereby cause plunger 96 to move to the left and allow plate 52 to descend a relatively short distance relative to plate 54. When this occurs, the tool moves into bonding relationship with wire 32 and forces the latter against the frame terminal for a predetermined period of time. At the end of this time period, timing motor 142 is automatically energized to rotate shaft 126 to cause it to complete its 360 arcuate travel and, when this occurs, homing cam 118 rotates so that its lobe 144 once again engages roller 146 to rotate lever 148 in a clockwise sense and thereby return slide unit 50 to the home position. The operator can then manipulate knob 46 to move mount 18 into a new position for bonding another location of the die to a second frame terminal. However, before this is done, torch 34 is automatically rotated so that its flame sweeps across the wire to cut the same and to form a bead on the wire for the next bond operation.

I claim:

1. A mechanical actuator comprising: a support; a cam mounted on the support for rotation relative thereto about a first axis; an actuator member mounted on the support for rotation about a second axis substantially parallel with the first axis and having a bearing surface spaced radially from and facing said second axis; a lever having first means for mounting the same for movement on the support in a direction transversely of said axes and second means adjacent to one end thereof for engaging said cam and said surface; and means biasing said second means into engagement with said cam and said surface, said member being movable into any one of a number of operative positions relative to said support to adjust the location of said surface relative to said cam.

2. An actuator as set forth in claim 1, wherein said member comprises a bearing having a crescent-shaped projection extending laterally therefrom, said surface being substantially flat and disposed on said projection.

3. An actuator for use in moving a tool comprising: a support; a shaft mounted on the support for rotation about a first axis; a cam rigidly mounted on said shaft for rotation therewith and having an outer cam edge; means defining a bearing surface; means mounting said surface defining means on the support adjacent to the first shaft for rotation about a second axis parallel to the first axis, said surface being radially spaced from and facing said second axis; a lever having bearing means at one end thereof for simultaneously engaging said cam edge and said surface, the lever being mounted on the support for movement relative thereto and transversely of said first and second axes in response to the movement of said bearing means along the surface and as a function of the rotation of the cam, said surface defining means having structure for adjustably rotating the same relative to said support; and

means coupled with the lever for biasing said bearing means toward and into engagement with the cam edge and said surface.

4. An actuator as set forth in claim 3, wherein said surface defining means includes a cylindrical member journaled on said support and having a crescent-shaped projection at one end thereof, said surface being on said projection and having opposed extremities adjacent to the outer periphery of said member.

5. An actuator as set forth in claim 3, wherein said bearing means includes roller structure mounted on said lever for rotation about an axis substantially parallel to said first and second axes.

6. An actuator as set forth in claim 3, and including means coupled with said shaft for rotating said cam about said first axis.

7. A mechanical actuator comprising: a support; a cam mounted on the support for rotation relative thereto about a first axis; an actuator member mounted on the support for rotation about a second axis substantially parallel with the first axis and having a bearing surface spaced radially from said second axis; a lever having means for mounting the same for movement on the support in a direction transversely of said axes, said lever having roller means at one end thereof normally engaging said cam and said surface; a spring coupled to said lever adjacent to its opposite end, said spring being operable to bias said roller means into engagement with said cam and said surface, said member being movable into any one of a number of operative positions relative to said support to adjust the location of said surface relative to said cam; an arm secured to and projecting transversely of said lever; and a shaft mounted on said support for rotation about a third axis substantially parallel with said first and second axes, said arm being rigid to said shaft and being operable to rotate the latter as the lever is moved along said surface in response to the rotation of the cam about said first axis.

8. An actuator as set forth in claim 7, wherein is included a slide unit shiftably mounted on the support for movement relative'thereto in response to the rotation of said shaft, the slide unit adapted to mount a tool thereon.

9. A mechanical actuator comprising: a support; a cam mounted on the support for rotation relative thereto about a first axis; an actuator member mounted on the support for rotation about a second axis substantially parallel with the first axis and having a bearing surface on one side of and facing said second axis; a lever having means for mounting the same for movement on the support in a direction transversely of said axes, said lever having roller means at one end thereof engageable with said cam and said surface; and means biasing said roller means into engagement with said cam and said surface, said member being movable into any one of a number of operative positions relative to said support to adjust the location of said surface relative to said cam.

10. An actuator as set forth in claim 9, wherein said roller means includes a pair of spaced rollers.

11. An actuator as set forth in claim 10, wherein said rollers are axially spaced from each other.

12. A mechanical actuator comprising: a support; a cam mounted on the support for rotation relative thereto about a first axis; an actuator member mounted on the support for rotation about a second axis substantially parallel with the first axis and having a bearing surface spaced radially from and facing said second axis; a lever having means for mounting the same for movement on the support in a direction transversely of said axes, said lever having roller means normally engaging said cam and said surface; means biasing said roller means into engagement with said cam and said surface, said member being movable into any one of a number of operative positions relative to said support to adjust the location of said surface relative to said cam; an arm secured to and projecting transversely of said lever; and a shaft mounted on said support for rotation about a third axis substantially parallel with said first and second axes, said arm being rigid to said shaft and being operable to rotate the latter as the lever is moved along said surface and as said lever moves transversely of said axes in response to the rotation of the cam about said first axis.

13. An actuator as set forth in claim 12, wherein said roller means includes a roller normally engaging said surface and having a central axis movable into coincidence with said second axis as said cam moves into a predetermined rotative position relative to said support.

14. An actuator for use in moving a tool comprising: a support; a shaft mounted on the support for rotation about a first axis; a cam rigidly mounted on said shaft for rotation therewith and having an outer cam edge; means defining a bearing surface; means mounting said surface defining means on the support adjacent to the first shaft for rotation about a second axis parallel to the first axis, said surface being radially spaced from and facing said second axis; a lever having bearing means for engaging said cam edge and said surface, the lever being mounted on the support for movement relative thereto and transversely of said first and second axes in response to the movement of said bearing means along the surface and as a function of the rotation of the cam, said surface defining means having structure for adjustably rotating the same relative to said support, said bearing means having a central axis movable into coincidence with the second axis when the cam is in a predetermined rotation position relative to said support; and means coupled with the lever for biasing said bearing means toward and into engagement with the cam edge and said surface.

15. An actuator as set forth in claim 14, wherein said bearing means includes a roller adjacent to one of said lever.

16. A mechanical actuator comprising: a support; a cam mounted on the support for rotation relative thereto about a first axis; an actuator member mounted on the support for rotation about a second axis substantially parallel with the first axis and having a bearing surface on one side of and facing said second axis; a lever having means for mounting the same for movement on the support in a direction transversely of said axes, said lever having roller means at one end thereof engageable with said cam and said surface; and means biasing said roller means into engagement with said cam and said surface, said member being movable into any one of a number of operative positions relative to said support to adjust the location of said surface relative to said cam, said roller means including a roller engageable with said surface and having a central axis movable into coincidence with said second axis when to said support. 

1. A mechanical actuator comprising: a support; a cam mounted on the support for rotation relative thereto about a first axis; an actuator member mounted on the support for rotation about a second axis substantially parallel with the first axis and having a bearing surface spaced radially from and facing said second axis; a lever having first means for mounting the same for movement on the support in a direction transversely of said axes and second means adjacent to one end thereof for engaging said cam and said surface; and means biasing said second means into engagement with said cam and said surface, said member being movable into any one of a number of operative positions relative to said support to adjust the location of said surface relative to said cam.
 2. An actuator as set forth in claim 1, wherein said member comprises a bearing having a crescent-shaped projection extending laterally therefrom, said surface being substantially flat and disposed on said projection.
 3. An actuator for use in moving a tool comprising: a support; a shaft mounted on the support for rotation about a first axis; a cam rigidly mounted on said shaft for rotation therewith and having an outer cam edge; means defining a bearing surface; means mounting said surface defining means on the support adjacent to the first shaft for rotation about a second axis parallel to the first axis, said surface being radially spaced from and facing said second axis; a lever having bearing means at one end thereof for simultaneously engaging said cam edge and said surface, the lever being mounted on the support for movement relative thereto and transversely of said first and second axes in response to the movement of said bearing means along the surface and as a function of the rotation of the cam, said surface defining means having structure for adjustably rotating the same relative to said support; and means coupled with the lever for biasing said bearing means toward and into engagement with the cam edge and said surface.
 4. An actuator as set forth in claim 3, wherein said surface defining means includes a cylindrical member journaled on said support and having a crescent-shaped projection at one end thereof, said surface being on said projection and having opposed extremities adjacent to the outer periphery of said member.
 5. An actuator as set forth in claim 3, wherein said bearing means includes roller structure mounted on said lever for rotation about an axis substantially parallel to said first and second axes.
 6. An actuator as set forth in claim 3, and including means coupled with said shaft for rotating said cam about said first axis.
 7. A mechanical actuator comprising: a support; a cam mounted on the support for rotation relative thereto about a first axis; an actuator member mounted on the support for rotation about a second axis substantially parallel with the first axis and having a bearing surface spaced radially from said second axis; a lever having means for mounting the same for movement on the support in a direction transversely of said axes, said lever having roller means at one end thereof normally engaging said cam and said surface; a spring coupled to said lever adjacent to its opposite end, said spring being operable to bias said roller means into engagement with said cam and said surface, said member being movable into any one of a number of operative positions relative to said support to adjust the locatIon of said surface relative to said cam; an arm secured to and projecting transversely of said lever; and a shaft mounted on said support for rotation about a third axis substantially parallel with said first and second axes, said arm being rigid to said shaft and being operable to rotate the latter as the lever is moved along said surface in response to the rotation of the cam about said first axis.
 8. An actuator as set forth in claim 7, wherein is included a slide unit shiftably mounted on the support for movement relative thereto in response to the rotation of said shaft, the slide unit adapted to mount a tool thereon.
 9. A mechanical actuator comprising: a support; a cam mounted on the support for rotation relative thereto about a first axis; an actuator member mounted on the support for rotation about a second axis substantially parallel with the first axis and having a bearing surface on one side of and facing said second axis; a lever having means for mounting the same for movement on the support in a direction transversely of said axes, said lever having roller means at one end thereof engageable with said cam and said surface; and means biasing said roller means into engagement with said cam and said surface, said member being movable into any one of a number of operative positions relative to said support to adjust the location of said surface relative to said cam.
 10. An actuator as set forth in claim 9, wherein said roller means includes a pair of spaced rollers.
 11. An actuator as set forth in claim 10, wherein said rollers are axially spaced from each other.
 12. A mechanical actuator comprising: a support; a cam mounted on the support for rotation relative thereto about a first axis; an actuator member mounted on the support for rotation about a second axis substantially parallel with the first axis and having a bearing surface spaced radially from and facing said second axis; a lever having means for mounting the same for movement on the support in a direction transversely of said axes, said lever having roller means normally engaging said cam and said surface; means biasing said roller means into engagement with said cam and said surface, said member being movable into any one of a number of operative positions relative to said support to adjust the location of said surface relative to said cam; an arm secured to and projecting transversely of said lever; and a shaft mounted on said support for rotation about a third axis substantially parallel with said first and second axes, said arm being rigid to said shaft and being operable to rotate the latter as the lever is moved along said surface and as said lever moves transversely of said axes in response to the rotation of the cam about said first axis.
 13. An actuator as set forth in claim 12, wherein said roller means includes a roller normally engaging said surface and having a central axis movable into coincidence with said second axis as said cam moves into a predetermined rotative position relative to said support.
 14. An actuator for use in moving a tool comprising: a support; a shaft mounted on the support for rotation about a first axis; a cam rigidly mounted on said shaft for rotation therewith and having an outer cam edge; means defining a bearing surface; means mounting said surface defining means on the support adjacent to the first shaft for rotation about a second axis parallel to the first axis, said surface being radially spaced from and facing said second axis; a lever having bearing means for engaging said cam edge and said surface, the lever being mounted on the support for movement relative thereto and transversely of said first and second axes in response to the movement of said bearing means along the surface and as a function of the rotation of the cam, said surface defining means having structure for adjustably rotating the same relative to said support, said bearing means having a central axis movable into coincidence with the second axis when the cam is in a predeterminEd rotation position relative to said support; and means coupled with the lever for biasing said bearing means toward and into engagement with the cam edge and said surface.
 15. An actuator as set forth in claim 14, wherein said bearing means includes a roller adjacent to one of said lever.
 16. A mechanical actuator comprising: a support; a cam mounted on the support for rotation relative thereto about a first axis; an actuator member mounted on the support for rotation about a second axis substantially parallel with the first axis and having a bearing surface on one side of and facing said second axis; a lever having means for mounting the same for movement on the support in a direction transversely of said axes, said lever having roller means at one end thereof engageable with said cam and said surface; and means biasing said roller means into engagement with said cam and said surface, said member being movable into any one of a number of operative positions relative to said support to adjust the location of said surface relative to said cam, said roller means including a roller engageable with said surface and having a central axis movable into coincidence with said second axis when said cam is in a predetermined rotative position relative to said support. 